In Drosophila, inhibitory interneurons are progressively recruited as olfactory sensory neurons are activated at increasing odor concentrations, allowing the flies to identify distinct odors at different intensities.

Final body size in the moth Manduca sexta can be predicted from the juvenile caterpillar by modeling three key growth measurements to reveal how growth rate, nutrition and temperature determine eventual body size.

Capuco and Akers review the biology of lactation and discuss a new report in Genome Biology that compares the bovine genome with six other mammalian genomes to study how lactation and its regulation evolved.

Rick Maizels discusses a recent paper in BMC Biology on wild mammals that lend support to the hygiene hypothesis, and explains why genetic variants that reduce parasite-induced immunosuppression are associated with an increase in allergic reactions.

Stephen Turner and colleagues follow up their earlier Q&A on influenza A (H1N1) 2009 and ask what we now know about its transmissibility, pathogenicity and variability, and the likelihood of more severe disease in the Northern hemisphere winter.

Major evolutionary change depends on changes in gene expression. Itay Tirosh and colleagues review recent research on the influence of promoter architecture and mutations in regulatory proteins on divergent expression patterns and suggest what is required for evolvability.

Stocker and colleagues identify and analyze a growth-promoting complex in Drosophila, formed between the putative transcription factor BunA, for which human homologs can functionally substitute, and the adaptor protein Madm.

Juan and Emerson discuss the reconstruction of the molecular phylogeny of a large Mediterranean cave-dwelling beetle clade recently presented in BMC Evolutionary Biology, and the implications for the evolutionary origin of the beetle ancestor.

Stem cell biology and new high throughput techniques are inspiring new advances in research on regeneration. Whited and Tabin discuss recent developments, including two recent reports in BMC Biology that may mean a reevaluation of the regenerative prospects for humans.

Hayward and colleagues discuss the promise of fluorescence resonance energy transfer (FRET)-based techniques to study the spatio-temporal subversion of host cell signaling by pathogens, reviewing the few existing examples of this, which include a recent paper in BMC Biology, to illustrate the power of an approach that has been surprisingly under-exploited to date.

Pinaud heralds the publication of the zebra finch genome, reviewing some of the most exciting findings of this pioneering effort and explaining how this songbird model offers unique insights into auditory learning, singing behaviour and other biological phenomena.

HIV causes immunodeficiency by deleting activated CD4 T lymphocytes, but paradoxically also causes general immune activation. Kassiotis and colleagues have mimicked this effect by using genetic engineering to delete activated T cells in mice, and show that in the mice it is due to loss of regulatory T cells.

Gardner, Bateman and Poole review the current knowledge of small nucleolar RNAs (snoRNAs) and discuss two BMC Genomic papers reporting the identification of novel snoRNAs and the likelihood that there are many more out there.

The bodies of platyhelminth and acoel worms are continually renewed from large pools of somatic stem cells. Bely and Sikes discuss their consequent attractiveness for stem cell research, and how recent studies, including one in BMC Developmental Biology, reveal aspects of the cellular dynamics and molecular basis of stem-cell function in these animals.

Jasinska and Freimer discuss a recent paper in BMC Biology by Mackay and colleagues that reveals the complex genetics behind fruitfly aggression, with implications for the dissection of human behaviours

Frank Slack and Samrat Kundu highlight a refinement of the antisense strategy used to inhibit miRNAs in C.elegans, published in Silence, with an adaptation that supports transmission through the germline, and combinatorial use to target several different miRNAs in developing tissues.

Christopher Barratt and colleagues review our current knowledge of the human sperm cell and available treatments for male subfertility in the light of a recent paper in BMC Developmental Biology on the role of the annulus.

Small molecules that stabilize mutant proteins with high specificity can be used to treat protein misfolding and metabolic diseases: in a Q&A highlighting recent successes, Dagmar Ringe and Gregory Petsko explain how.